<!DOCTYPE html>
<html>
<head>
    <title>Array map() Example</title>
</head>
<body>
    <script>
        var numbers = [1,2,3,4,5,4,3,2,1];
        
        var mapResult = numbers.map(function(item, index, array){
            return item * 2;
        });
        
        alert(mapResult);   //[2,4,6,8,10,8,6,4,2]

    </script>
</body>
</html>
